ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2001-2019 Free Software Foundation, Inc.
   3 #
   4 # This file is part of the GNU Binutils.
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19 # MA 02110-1301, USA.
  20 #
  21
  22 # This file is sourced from generic.em.
  23
  24 fragment <<EOF
  25 /* Need to have this macro defined before mmix-elfnmmo, which uses the
  26    name for the before_allocation function, defined in ldemul.c (for
  27    the mmo "emulation") or in elf.em (for the elf64mmix
  28    "emulation").  */
  29 #define gldmmo_before_allocation before_allocation_default
  30
  31 /* We include this header *not* because we expect to handle ELF here
  32    but because we use the map_segments function.  But this is only to
  33    get a weird testcase right; ld-mmix/bpo-22, forcing ELF to be
  34    output from the mmo emulation: -m mmo --oformat elf64-mmix!  */
  35 #include "ldelfgen.h"
  36
  37 static void gld${EMULATION_NAME}_after_allocation (void);
  38 EOF
  39
  40 source_em ${srcdir}/emultempl/elf-generic.em
  41 source_em ${srcdir}/emultempl/mmix-elfnmmo.em
  42
  43 fragment <<EOF
  44
  45 /* Place an orphan section.  We use this to put random SEC_CODE or
  46    SEC_READONLY sections right after MMO_TEXT_SECTION_NAME.  Much borrowed
  47    from elf.em.  */
  48
  49 static lang_output_section_statement_type *
  50 mmo_place_orphan (asection *s,
  51                   const char *secname,
  52                   int constraint ATTRIBUTE_UNUSED)
  53 {
  54   static struct
  55   {
  56     flagword nonzero_flags;
  57     struct orphan_save orphansave;
  58   } holds[] =
  59       {
  60         {
  61           SEC_CODE | SEC_READONLY,
  62           {
  63             MMO_TEXT_SECTION_NAME,
  64             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE,
  65             0, 0, 0, 0
  66           }
  67         },
  68         {
  69           SEC_LOAD | SEC_DATA,
  70           {
  71             MMO_DATA_SECTION_NAME,
  72             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_DATA,
  73             0, 0, 0, 0
  74           }
  75         },
  76         {
  77           SEC_ALLOC,
  78           {
  79             ".bss",
  80             SEC_ALLOC,
  81             0, 0, 0, 0
  82           }
  83         }
  84       };
  85
  86   struct orphan_save *place = NULL;
  87   lang_output_section_statement_type *after;
  88   lang_output_section_statement_type *os;
  89   size_t i;
  90   flagword flags;
  91   asection *nexts;
  92
  93   /* We have nothing to say for anything other than a final link or
  94      for sections that are excluded.  */
  95   if (bfd_link_relocatable (&link_info)
  96       || (s->flags & SEC_EXCLUDE) != 0)
  97     return NULL;
  98
  99   os = lang_output_section_find (secname);
 100
 101   /* We have an output section by this name.  Place the section inside it
 102      (regardless of whether the linker script lists it as input).  */
 103   if (os != NULL)
 104     {
 105       lang_add_section (&os->children, s, NULL, os);
 106       return os;
 107     }
 108
 109   flags = s->flags;
 110   if (!bfd_link_relocatable (&link_info))
 111     {
 112       nexts = s;
 113       while ((nexts = bfd_get_next_section_by_name (nexts->owner, nexts))
 114              != NULL)
 115         if (nexts->output_section == NULL
 116             && (nexts->flags & SEC_EXCLUDE) == 0
 117             && ((nexts->flags ^ flags) & (SEC_LOAD | SEC_ALLOC)) == 0
 118             && (nexts->owner->flags & DYNAMIC) == 0
 119             && nexts->owner->usrdata != NULL
 120             && !(((lang_input_statement_type *) nexts->owner->usrdata)
 121                  ->flags.just_syms))
 122           flags = (((flags ^ SEC_READONLY) | (nexts->flags ^ SEC_READONLY))
 123                    ^ SEC_READONLY);
 124     }
 125
 126   /* Check for matching section type flags for sections we care about.
 127      A section without contents can have SEC_LOAD == 0, but we still
 128      want it attached to a sane section so the symbols appear as
 129      expected.  */
 130
 131   if ((flags & (SEC_ALLOC | SEC_READONLY)) != SEC_READONLY)
 132     for (i = 0; i < sizeof (holds) / sizeof (holds[0]); i++)
 133       if ((flags & holds[i].nonzero_flags) != 0)
 134         {
 135           place = &holds[i].orphansave;
 136           if (place->os == NULL)
 137             place->os = lang_output_section_find (place->name);
 138           break;
 139         }
 140
 141   if (place == NULL)
 142     {
 143       /* For other combinations, we have to give up, except we make
 144          sure not to place the orphan section after the
 145          linker-generated register section; that'd make it continue
 146          the reg section and we never want that to happen for orphan
 147          sections.  */
 148       lang_output_section_statement_type *before;
 149       lang_output_section_statement_type *lookup;
 150       static struct orphan_save hold_nonreg =
 151         {
 152           NULL,
 153           SEC_READONLY,
 154           0, 0, 0, 0
 155         };
 156
 157       if (hold_nonreg.os == NULL)
 158         {
 159           before = lang_output_section_find (MMIX_REG_CONTENTS_SECTION_NAME);
 160
 161           /* If we have no such section, all fine; we don't care where
 162              it's placed.  */
 163           if (before == NULL)
 164             return NULL;
 165
 166           /* We have to find the oss before this one, so we can use that as
 167              "after".  */
 168           for (lookup = &lang_os_list.head->output_section_statement;
 169                lookup != NULL && lookup->next != before;
 170                lookup = lookup->next)
 171             ;
 172
 173           hold_nonreg.os = lookup;
 174         }
 175
 176       place = &hold_nonreg;
 177     }
 178
 179   after = place->os;
 180   if (after == NULL)
 181     return NULL;
 182
 183   /* If there's an output section by *this* name, we'll use it, regardless
 184      of actual section flags, in contrast to what's done in elf.em.  */
 185   os = lang_insert_orphan (s, secname, 0, after, place, NULL, NULL);
 186
 187   return os;
 188 }
 189
 190 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 191    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 192    paper over the bug similarly.  */
 193
 194 static void
 195 mmo_wipe_sec_reloc_flag (bfd *abfd ATTRIBUTE_UNUSED, asection *sec,
 196                          void *ptr ATTRIBUTE_UNUSED)
 197 {
 198   bfd_set_section_flags (sec, bfd_section_flags (sec) & ~SEC_RELOC);
 199 }
 200
 201 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 202
 203 static void
 204 gld${EMULATION_NAME}_after_allocation (void)
 205 {
 206   bfd_map_over_sections (link_info.output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 207   ldelf_map_segments (FALSE);
 208 }
 209 \f
 210 /* To get on-demand global register allocation right, we need to parse the
 211    relocs, like what happens when linking to ELF.  It needs to be done
 212    before all input sections are supposed to be present.  When linking to
 213    ELF, it's done when reading symbols.  When linking to mmo, we do it
 214    when all input files are seen, which is equivalent.  */
 215
 216 static void
 217 mmo_after_open (void)
 218 {
 219   /* When there's a mismatch between the output format and the emulation
 220      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 221      example), we'd count relocs twice because they'd also be counted
 222      along the usual route for ELF-only linking, which would lead to an
 223      internal accounting error.  */
 224   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 225     {
 226       LANG_FOR_EACH_INPUT_STATEMENT (is)
 227         {
 228           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 229               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 230             einfo (_("%X%P: internal problems scanning %pB after opening it"),
 231                    is->the_bfd);
 232         }
 233     }
 234   after_open_default ();
 235 }
 236 EOF
 237
 238 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 239 LDEMUL_AFTER_OPEN=mmo_after_open